Edge adaptive de-interlacing apparatus and method thereof

ABSTRACT

An edge adaptive de-interlacing apparatus and method are disclosed. The edge adaptive de-interlacing apparatus includes a complexity detection module, a qualifier, a comparator and a mixer. The complexity detection module detects complexity associated with a target pixel. The qualifier is coupled to the complexity detection module for generating similarity of at least one possible edge angle in response to the complexity. The comparator is coupled to the qualifier for comparing the similarity of the at least one possible edge to select a preferred edge angle. The mixer is coupled to the comparator for generating pixel data of the target pixel according to the preferred edge angle.

This application claims the benefit of Taiwan application Serial No.95103568, filed Jan. 27, 2006, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to an edge adaptive de-interlacingapparatus and associated method, and more particularly to an edgeadaptive de-interlacing apparatus and method, which can accuratelyobtain an edge angle by detecting extreme values or complexity of aregion surrounding a target pixel.

2. Description of the Related Art

Conventional TV programs are transmitted and displayed in an interlacedway. Take television as an example, and in a process of displaying aframe, it displays an odd field and an even field alternatively. The oddfield is composed of odd numbers of display lines in the frame while theeven field is composed of even numbers of display lines in the frame.

The refresh rate of a television is normally 30 Hz, that is, 30 framesper second are displayed. Each frame is divided into an odd field and aneven field for display. Therefore, there are 60 fields in one second fordisplay.

Owing that progressive display has a higher quality than the interlaceddisplay, an advanced display apparatus can perform de-interlacingdisplay, such as a high definition TV (HDTV).

If the interlaced fields are to be displayed in a de-interlacing way,the interlaced fields should be de-interlaced first and then displayedin complete frames. There are two de-interlacing method. The firstmethod is to merge the adjacent odd field and even field into a completeframe. This kind of method easily causes a saw-tooth effect on a movingpicture, thereby influencing a frame quality.

The second de-interlacing method is to interpolate the missing displaylines in the odd field or even field. The above-mentioned missingdisplay lines are generated by respectively interpolating for eachtarget pixel by using two vertical adjacent display lines in the samefield.

When interpolating a missing line in the same field, a target pixel inthat display line is used as a center to find out every possible edgeangle and then an edge angle is selected. Finally, a color value of thetarget pixel is interpolated according to the selected edge angle.

However, the quality of the frame generated by interpolating displaylines is determined by whether the selected edge angle is correct.Selecting a wrong edge angle will result in interpolating incorrectcolor values for the target pixel and bad interpolated image quality.

SUMMARY OF THE INVENTION

The invention provides an edge adaptive de-interlacing apparatus andmethod thereof. By detecting extreme values or complexity of twoadjacent display lines, a preferred edge angle can be found and properpixel data can be interpolated in between the above two display lines toavoid frame distortion due to selection of an incorrect edge angle.

According to a first aspect of the present invention, an edge adaptivede-interlacing apparatus for de-interlacing a target pixel including acomplexity detection module, a qualifier, a comparator and a mixer isprovided. The complexity detection module detects complexity associatedwith the target pixel. The qualifier is coupled to the complexitydetection module for generating similarity of at least one possible edgeangle in response to the complexity. The comparator is coupled to thequalifier for selecting a preferred edge angle according to thesimilarity of the at least one possible edge. The mixer is coupled tothe comparator for generating pixel data of the target pixel accordingto the preferred edge angle.

According to a second aspect of the present invention, an edge adaptivede-interlacing method for de-interlacing a target pixel is provided. Themethod includes detecting complexity associated with the target pixel;generating similarity of at least one possible edge angle in response tothe complexity; selecting a preferred edge angle according to the atleast one possible edge angle; and generating pixel data of the targetpixel according to the preferred edge angle.

According to a third aspect of the present invention, an edge adaptivede-interlacing method for de-interlacing a target pixel is provided. Themethod includes detecting complexity associated with the target pixel;performing an adaptive edge detection according to the complexity todetermine a preferred edge angle; and de-interlacing pixel data of thetarget pixel according to the preferred edge angle.

According to a fourth aspect of the present invention, an edge adaptivede-interlacing apparatus for de-interlacing a target pixel including anextreme-value detection module, a qualifier, a comparator, and a mixeris provided. The extreme-value detection module is for detecting atleast an extreme-value position of a luminance distribution curve in afirst region related to the target pixel and accordingly outputting aprediction signal for indicating a predicted angle region. The qualifieris coupled to the extreme-value detection module for generatingsimilarity of at least one possible edge angle in response to thepredicted angle region. The comparator is coupled to the qualifier forselecting a preferred edge angle according to the similarity of the atleast one possible edge angle. The mixer is coupled to the comparatorfor generating pixel data of the target pixel according to the preferrededge angle.

According to a fifth aspect of the present invention, an edge adaptivede-interlacing method for de-interlacing a target pixel is provided. Themethod includes detecting at least an extreme-value position of thefield surrounding the target pixel and accordingly outputting aprediction signal for indicating a predicted angle region; generatingsimilarity of at least one possible edge angle in response to thepredicted angle region; selecting a preferred edge angle according tothe similarity of the at least one possible edge angle; and generatingpixel data of the target pixel according to the preferred edge angle.

The invention will become apparent from the following detaileddescription of the preferred but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a first display line, a second displayline and a pixel of a to-be-interpolated display line.

FIG. 2 is a block diagram of a de-interlacing apparatus according to afirst embodiment of the invention.

FIG. 3 is a flow chart of a de-interlacing method applied to thede-interlacing apparatus in FIG. 2 according to an embodiment of theinvention.

FIG. 4 is a block diagram of a de-interlacing apparatus according to asecond embodiment of the invention.

FIG. 5 is a flow chart of a de-interlacing method applied to the abovede-interlacing apparatus in FIG. 4 according to a preferred embodimentof the invention.

FIG. 6 is a block diagram of a de-interlacing apparatus according to athird embodiment of the invention.

FIG. 7 is a flow chart of a de-interlacing method applied to thede-interlacing apparatus in FIG. 6 according to a preferred embodimentof the invention

DETAILED DESCRIPTION OF THE INVENTION

The de-interlacing apparatus transforms an interlaced image into ade-interlacing image for output such that a preferred edge angle can beobtained for accordingly interpolating the absent display linescorrectly in an odd field or even field. In the embodiment, by detectingcomplexity of, for example, a first display line and a second displayline located adjacently the to-be-interpolated display line, the correctedge angle can be found out for providing a delicate image frame.

Referring to FIG. 1, a schematic diagram of a first display line, asecond display line and a to-be-interpolated display line associatedwith a target pixel is shown. The first display line L⁻¹ includes pixelsP1˜Pn, the to-be-interpolated display line L₀ includes pixels P1′˜Pn′,and the second display line L₊₁ includes pixels P1″˜Pn″.

When interpolating a target pixel of the to-be-interpolated display lineL₀ between the first display line L⁻¹ and the second display line L₊₁,the de-interlacing apparatus selects a part of pixels of the firstdisplay line L⁻¹ and the second display line L₊₁ related to the targetpixel according to extreme values or complexity of luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁.

Possible edge angles are represented between the selected part of pixelsand the target pixel. The de-interlacing apparatus finds out a preferrededge angle from all the possible edge angles to interpolate proper pixeldata, such as grey values, for the target pixel.

For example, when interpolating pixel data of the target pixel P100′ ofthe to-be-interpolated display line L₀, the de-interlacing apparatusselects pixels P81˜P119 of the first display line L⁻¹ and pixelsP81″˜P119″ of the second display line L₊₁ symmetrically to the targetpixel P100′ according to extreme values or complexity of the firstdisplay line L⁻¹ and the second display line L₊₁. A plurality ofpossible edge angles are represented by the target pixel P100′, thepixels P81˜P119 and the pixels P81″˜P119″. For example, the pixels P100and P100″ and the target pixels P100′ represent a possible edge angleAngle0, the pixel P99 and P101″ and the target pixel P100′ represent apossible edge angle Angle−1, and the pixels P101 and P99″ and the targetpixel P100′ represent a possible edge angle Angle+1. It can beanalogized that the pixels P81-P119 and P81″˜P119″ and the target pixelP100′ form 39 possible edge angles. The de-interlacing apparatus thenfinds out a preferred edge angle from the 39 possible edge angles andinterpolates proper pixel data according to the preferred edge angle.

Embodiment One

Referring to FIG. 2, a block diagram of a de-interlacing apparatusaccording to a first embodiment of the invention is shown. Ade-interlacing apparatus 20(1) includes a first memory 210, a secondmemory 220, a complexity detection module 230, a qualifier 240, acomparator 250 and a mixer 260. The complexity detection module 230includes a first complexity detector 232, a second complexity detector234 and a logic operation unit 236. The first memory 210 stores theabove first display line L⁻¹ and the second memory 220 stores the abovesecond display line L₊₁ (as shown in FIG. 1).

The first complexity detector 232 detects a first complexity of thefirst display line L⁻¹ in a first region corresponding to the targetpixel. Pixel data of the pixels in the first region can be representedby a luminance distribution curve with reference to their pixelpositions. The first complexity detector 232 outputs a firstdetermination signal S1 according to complexity of the distributioncurve of the first display line L⁻¹. For example, the firstdetermination signal S1 includes a plurality of first flags forindicating whether complexity of the first display line L⁻¹ in the firstregion exceeds a threshold value. For example, complexity of apredetermined region can be determined by the amount of extreme valuesin that region. When images in the region have a lot of extreme values,it represents brightness of images in that region varies very severelyand image complexity is high, and otherwise, image complexity is low.

Similarly, the second complexity detector 234 detects a secondcomplexity of the second display line L₊₁ in a first regioncorresponding to the target pixel. Relationship of pixel data of pixelsin the first region relative to their pixel positions can be representedby a luminance distribution curve. The second complexity detector 234outputs a second determination signal S2 according to complexity of theluminance distribution curve of the second display line L₊₁. Forexample, the second determination signal S2 includes a plurality ofsecond flags for indicating whether complexity of the second displayline L₊₁ in the first region exceeds a threshold value.

The first determination signal S1 and the second determination signal S2are respectively output to the logic operation unit 236. The logicoperation unit 236 performs a logic operation, such as a logic ORoperation or a logic AND operation, according to the first determinationsignal S1 and the second determination signal S2 and outputs a controlsignal S3 for indicating a second region to the qualifier 234 after thelogic operation. Preferably, if the logic operation unit 236 performsthe logic OR operation, it determines the luminance distribution iscomplicated when at least one of complexity of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ exceeds the threshold value. Alternatively, if the logicoperation is a logic AND operation, it determines the luminancedistribution is complicated only when complexity of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ both exceeds the threshold value. Thus, the proper secondregion is determined accordingly.

The qualifier 240 receives the control signal S3 and generatessimilarity Q of possible edge angles of pixel pairs of the first displayline L⁻¹ and the second display line L₊₁ in the second region. Forexample, the similarity Q quantizes probability of every possible edgeangle to become a preferred edge angle, which can be determined by, forexample, whether there exist determined angles in the same directionamong the neighboring pixels.

The comparator 250 receives the similarity Q outputted by the qualifier249 and compares the similarity Q of each possible edge angle forselecting a preferred edge angle A accordingly. The mixer 260interpolates pixel data D for the target pixel according to thepreferred edge angle. For example, the mixer 260 obtains an averagevalue or a weighting average of pixel data of the pixels on thepreferred edge angel A.

Referring to FIG. 3, a flow chart of a de-interlacing method applied tothe above de-interlacing apparatus 20(1) according to an embodiment ofthe invention is shown. First, in step 310, the complexity detectionmodule 230 outputs the control signal S3 for indicating the secondregion according to complexity of luminance distribution curves of thefirst display line L⁻¹ and the second display line L₊₁ in the firstregion corresponding to the target pixel.

Next, in step 320, the qualifier 240 receives the control signal S3, andgenerates the similarity Q of the possible edge angles of pixel pairs ofthe first display line L⁻¹ and the second display line L₊₁ in the secondregion. In step 330, the comparator 250 compares the similarity Q andselects the preferred edge angle A from the possible edge angles.Finally, in step 340, the mixer 260 generates the pixel data D of thetarget pixel according to the preferred edge angle A.

For example, when the frame contains characters for display, itscomplexity is higher. Contrarily, when the frame shows pictures, itscomplexity is lower. Therefore, when the de-interlacing apparatus 20(1)is to interpolate pixel data of the target pixel P100′ of theto-be-interpolated display line L₀ (as shown in FIG. 1), the complexitydetection module 230 outputs the control signal S3 according tocomplexity of the luminance distribution curves of the first displayline L⁻¹ and the second display line L₊₁ in the first regioncorresponding to the target pixel P100′. For example, the pixels in thefirst region of the first display line L⁻¹ are pixels P75˜P125, and thepixels in the first region of the second display line L₊₁ are pixelP75″˜P125″.

Preferably, when complexity of the luminance distribution curves of thepixels P75˜P125 and P75″˜P125″ is smaller than a threshold value, thede-interlacing apparatus 20(1) selects a larger second region and thepixels in the larger second region of the first display line L⁻¹ arepixels P90˜P110 and the pixels in the larger second region of the seconddisplay line L₊₁ are pixels P90″˜P110″ for instance.

Preferably, when complexity is larger than a threshold value, thede-interlacing apparatus 20(1) selects a smaller second region to avoida wrong determination of a preferred edge angle. The pixels in thesmaller second region of the first display line L⁻¹ are pixels P95˜P105and the pixels in the smaller second region of the second display lineL₊₁ are pixels P95″˜P105″ for instance.

In this way, when the complexity is high, the de-interlacing apparatus20(1) finds out the preferred edge angle from the smaller second regionand interpolates proper pixel data according to the preferred edge angleto avoid a wrong selection of the preferred edge angle due to usage ofan overlarge region. For example, as processing pixels, a window candefine a processing region. The sizes of the window and the above regionare associated with a predetermined number of the display lines to beconsidered in the surrounding. In this embodiment, the first displayline L⁻¹ and the second display line L₊₁ are taken as an example.

Embodiment Two

Referring to FIG. 4, a block diagram of a de-interlacing apparatusaccording to a second embodiment of the invention is shown. In theembodiment, an extreme-value detection module 270 detects extreme valuesof the first display line L⁻¹ and the second display line L₊₁ in a thirdregion corresponding to the target pixel. For example, when each of theluminance distribution curves of the first display line L⁻¹ and thesecond display line L₊₁ in the third region has an extreme value, aprediction signal S6 is outputted for indicating a predicted angleregion of possible edge angles. The de-interlacing apparatus 20(2) canthus more accurately find out a preferred edge angle from the predictedangle region for interpolating pixel data.

The extreme-value detection module 270 includes a first extreme-valuedetector 272, a second extreme-value detector 274 and an angle predictor276. The first extreme-value predictor 272 detects extreme values of aluminance distribution curve of the first display line L⁻¹ in the thirdregion and outputting a first extreme-value signal S4 according to atleast one position(s) of the extreme values of the luminancedistribution curve. For example, the extreme value of each display linecan be determined by using a first-order differential calculation. Anextreme value exists where the differential value varies its positive ornegative sign, i.e. a change of positive or negative sign in thedifferential operation.

Similarly, the second extreme-value detector 274 detects extreme valuesof a luminance distribution curves of the second display line L₊₁ in thethird region and outputting a second extreme-value signal S5 accordingto at least one position(s) of the extreme values of the luminancedistribution curve.

When each of the luminance distribution curves of the first display lineL⁻¹ and the second display line L₊₁ has an extreme value, the anglepredictor 276 outputs a prediction signal S6 for indicating a predictedangle region according to the first extreme-value signal S4 and thesecond extreme-value signal S5.

The qualifier 240 receives the prediction signal S6 and generatessimilarity Q′ of possible edge angles of pixel pairs of the firstdisplay line L⁻¹ and the second display line L₊₁ corresponding to thepredicted angel region.

The comparator 250 receives the similarity Q′ outputted by the qualifier240 and compares the similarity Q′ of the possible edge angles to selecta preferred edge angle A′. The mixer 260 generates pixel data D′ of thetarget pixel according to the preferred edge angle A′.

FIG. 5 shows a flow chart of a de-interlacing method applied to theabove de-interlacing apparatus 20(2) according to a preferred embodimentof the invention. First, in step 510, the extreme-value detection module270 detects the first display line L⁻¹ and the second display line L₊₁in the third region. When each of the luminance distribution curves ofthe first display line L⁻¹ and the second display line L₊₁ in the thirdregion with reference to the target pixel, a prediction signal S6 isoutputted to indicate a predicted angle region of the possible edgeangles.

Next, in step 520, the qualifier 240 receives the prediction signal S6and generates the similarity Q′ of the possible edge anglescorresponding to the predicted angle region. In step 530, the comparator250 compares the similarity Q′ to select the preferred edge angle A′from the possible edge angles. Finally, in step 540, the mixer 260generates pixel data D′ of the target pixel according to the preferrededge angle A′.

For example, when the de-interlacing apparatus 20(2) interpolates pixeldata of the target pixel P100′ of the to-be-interpolated display line L0(as shown in FIG. 1), the extreme-value detection module 270 outputs theprediction signal S6 according to the extreme values of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ in the third region with reference to the target pixel P100′.The pixels in the third region of the first display line L⁻¹ are pixelsP75˜P125 and the pixels in the third region of the second display lineL₊₁ are pixels P75″˜P125″ for instance. When detecting the extremevalues on the pixel P102 of the first display line L⁻¹, for example, thefirst extreme-value detector 272 outputs the first extreme-value signalS4 to the angle predictor 276. Similarly, when detecting out extremevalues on the pixel P98″ of the second display line L₊₁, for example,the second extreme-value detector 274 outputs the second extreme-valuesignal S5 to the angle predictor 276. The angle predictor 276 generatesthe prediction signal S6 to the qualifier 240 for indicating thepredicted angle region according to the first extreme-value signal S4and the second extreme-value signal S5. In this embodiment, thepredicted angle region may encompass pixels P101˜P103 and P97″˜P99″. Thede-interlacing apparatus 20(2) finds out a preferred edge angle from thepossible edge angles represented by the pixels P101˜P103 and P97″˜P99″and the target pixel P100′ in order to interpolate the pixel dataaccording to the preferred edge angle.

Embodiment Three

Referring to FIG. 6, a block diagram of a de-interlacing apparatusaccording to a third embodiment of the invention is shown. Ade-interlacing apparatus 20(3) respectively detects extreme valuesand/or complexity of the first display line L⁻¹ and the second displayline L₊₁ via the extreme-value detection module 270 and the complexitydetection module 230 to accurately find out the preferred edge angle forinterpolating proper pixel data.

FIG. 7 shows a flow chart of a de-interlacing method applied to theabove de-interlacing apparatus 20(3) according to a preferred embodimentof the invention. First, in step 710, when each of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ has an extreme value within the third region with respect tothe target pixel, the extreme-value detection module 270 outputs theprediction signal S6 to indicate a predicted angle region of thepossible edge angles.

Next, in step 720, if the luminance distribution curves of the firstdisplay line L⁻¹ and the second display line L₊₁ in the third regionwith reference to the target pixel have a plurality of extreme values,the complexity detection module 230 outputs the control signal S3 toindicate a second region according to the complexity of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ in the first region with reference to the target pixel.Preferably, in the second region, at least one of the first display lineL⁻¹ and the second display line L₊₁ has complexity smaller than athreshold value.

In step 730, the qualifier generates similarity Q″ of the possible edgeangles of pixel pairs of the first display line L⁻¹ and the seconddisplay line L₊₁ in the second region or the predicted angle regionaccording to the control signal S3 and/or the prediction signal S6.

In step 740, the comparator 250 compares the similarity Q″ to select apreferred edge angle A″ from the possible edge angles. Finally, in step750, the mixer 260 generates pixel data D″ of the target pixel accordingto the preferred edge angle A″.

For example, when the de-interlacing apparatus 20(3) interpolates pixeldata of the target pixel P100′ of the to-be-interpolated display line L₀(as shown in FIG. 1), the extreme-value detection module 270 outputs theprediction signal S6 according to the extreme values of the luminancedistribution curves of the first display line L⁻¹ and the second displayline L₊₁ in the third region with reference to the target pixel P100′.The third region of the first display line L⁻¹ includes pixels P75˜P125and the third region of the second display line L₊₁ includes pixelsP75″˜P125″ for instance.

Preferably, when each of the luminance distribution curves of the firstdisplay line L⁻¹ and the second display line L₊₁ in the third region hasan extreme value, for example, the extreme-value detection module 270detects the extreme values from the pixel P102 of the first display lineL⁻¹ and the pixel P98″ of the second display line L₊₁, the extreme-valuedetection module 270 outputs the prediction signal to indicate aprediction angle region, including the pixels P101˜P103 and P97″˜P99″for instance.

The qualifier 240 generates the similarity Q″ of the possible edgeangles represented by the pixels P101˜P103 and P97″˜P99″ and the targetpixel P100′. The comparator 250 selects the preferred edge angle A″ fromthe similarity Q″ of the possible edge angles and the mixer 260generates the pixel data D″ of the target pixel according to thepreferred edge angle A″.

On the other hand, when the luminance distribution curves of the firstdisplay line L⁻¹ and the second display line L₊₁ in the third regionhave a plurality of extreme values, the complexity detection module 230outputs the control signal S3 to indicate a second region according tothe complexity of the luminance distribution curves of the first displayline L⁻¹ and the second display line L₊₁ in a first region correspondingto the target pixel. The first region of the first display line L⁻¹includes pixels P75˜P125 and the first region of the second display lineL₊₁ includes pixels P75″˜P125″ for instance.

The control signal S3 controls the qualifier 240 to generate thesimilarity Q″ of the possible edge angles of pixel pairs of the firstdisplay line L⁻¹ and the second display line L₊₁ in the second region.For example, the pixels of the first display line L⁻¹ in the secondregion include pixels P90˜P110 and the pixels of the second display lineL₊₁ in the second region include pixels P90″˜P110″. The comparator 250compares the similarity Q″ of the possible edge angles to select thepreferred edge angle A″. The mixer 260 generates the pixel data D″ ofthe target pixel according to the preferred edge angle A″.

As mentioned above, the invention discloses an edge adaptivede-interlacing apparatus for de-interlacing a target pixel including acomplexity detection module, a memory module, a qualifier, a comparatorand a mixer. The complexity detection module detects complexitysurrounding the target pixel in the field and the complexity representsan amount of extreme values existed in a region surrounding the targetpixel. The memory module, such as a line buffer of a liquid crystaldisplay (LCD) controller, is coupled to the complexity detection modulefor storing a plurality of display lines. For example, the memory moduleincludes a first memory for storing a first display line and a secondmemory for storing a second display line. The qualifier is coupled tothe complexity detection module for generating at least one possibleedge angle(s) in response to the complexity. The comparator is coupledto the qualifier for selecting the preferred edge angle from the atleast one possible edge angle by comparing the at least one possibleedge angle(s). The mixer is coupled to the comparator for generatingpixel data of the target pixel according to the preferred edge angle.For example, the mixer interpolates the pixel data of the target pixelby using a first display line and a second display line adjacent to thetarget pixel.

The invention discloses an edge adaptive de-interlacing method forde-interlacing a target pixel. First, detect complexity surrounding thetarget pixel in the field. Then, perform an adaptive edge detectionaccording to the complexity to determine a preferred edge angle. Forexample, a window processing region is determined according to thecomplexity. The higher the complexity is, the smaller the windowprocessing region is chosen. Inversely, the lower the complexity is, thelarger the window processing region is chosen. Finally, interpolate thepixel data of the target pixel according to the preferred edge angle.

The edge adaptive de-interlacing apparatus and method disclosed by theabove embodiment of the invention can accurately find out the preferrededge angle for providing a delicate image frame by detecting extremevalues and/or complexity of the luminance distribution curves ofadjacent display lines.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. An edge adaptive de-interlacing apparatus for de-interlacing a targetpixel, comprising: a complexity detection module, for detectingcomplexity associated with the target pixel, wherein the complexitydetection module comprises: a first complexity detector, for detecting afirst complexity of a luminance distribution curve of a first displayline in a first region associated with the target pixel to output afirst determination signal; a second complexity detector, for detectinga second complexity of a luminance distribution curve of a seconddisplay line in the first region to output a second determinationsignal; and a logic operational unit, for performing a logic operationaccording to the first determination signal and the second determinationsignal to output a control signal; a qualifier, coupled to thecomplexity detection module, for generating similarity of at least onepossible edge angle in response to the control signal; a comparator,coupled to the qualifier for comparing said similarity of the at leastone possible edge to select a preferred edge angle; and a mixer, coupledto the comparator for generating pixel data of the target pixelaccording to the preferred edge angle.
 2. The edge adaptivede-interlacing apparatus according to claim 1, wherein the mixergenerates the pixel data of the target pixel by interpolating the firstdisplay line and the second display line adjacent to the target pixel.3. The edge adaptive de-interlacing apparatus according to claim 2,wherein the control signal indicates a second region to the qualifierand the qualifier generates similarity of possible edge angles of pixelpairs of the first display line and the second display line in thesecond region.
 4. The edge adaptive de-interlacing apparatus accordingto claim 1, further comprising a memory module coupled to the complexitydetection module.
 5. The edge adaptive de-interlacing apparatusaccording to claim 4, wherein the memory module is a line buffer.
 6. Theedge adaptive de-interlacing apparatus according to claim 4, wherein thememory module comprises: a first memory, for storing the first displayline; and a second memory, for storing the second display line.
 7. Theedge adaptive de-interlacing apparatus according to claim 1, wherein thecomplexity associated with the target pixel represents an amount ofextreme-values existed in the first region.
 8. The edge adaptivede-interlacing apparatus according to claim 7, wherein the amount ofextreme values existed in the first region is obtained by a differentialcalculation.
 9. The edge adaptive de-interlacing apparatus according toclaim 1, wherein the logic operation is a logic OR operation or a logicAND operation.
 10. The edge adaptive de-interlacing apparatus accordingto claim 1, wherein the first determination signal comprises a pluralityof first flags for indicating the first complexity of the luminancedistribution curve of the first display line.
 11. The edge adaptivede-interlacing apparatus according to claim 1, wherein the seconddetermination signal comprises a plurality of second flags forindicating the second complexity of the luminance distribution curve ofthe second display line.
 12. The edge adaptive de-interlacing apparatusaccording to claim 1, further comprising an extreme-value detectionmodule for detecting positions of extreme values in a third regionassociated with the target pixel to output a prediction signal forindicating a predicted angle region.
 13. The edge adaptivede-interlacing apparatus according to claim 12, wherein theextreme-value detection module outputs the prediction signal to indicatethe predicted angle region when each of luminance distribution curves ofthe first display line and a the second display line in the third regionassociated with the target pixel has an extreme value.
 14. An edgeadaptive de-interlacing method for de-interlacing a target pixel,comprising: detecting complexity associated with the target pixel,comprising: detecting a first complexity of a luminance distributioncurve of a first display line in a first region associated with thetarget pixel to output a first determination signal; detecting a secondcomplexity of a luminance distribution curve of a second display line inthe first region to output a second determination signal; and performinga logic operation according to the first determination signal and thesecond determination signal to output a control signal; generatingsimilarity of at least one possible edge angle in response to thecontrol signal; selecting a preferred edge angle according to the atleast one possible edge angle; and generating pixel data of the targetpixel according to the preferred edge angle.
 15. The de-interlacingmethod according to claim 14, wherein the in the step of generatingpixel data, the pixel data of the target pixel are generated byinterpolating the first display line and the second display lineadjacent to the target pixel.
 16. The de-interlacing method according toclaim 14, wherein the complexity associated with the target pixelrepresents an amount of extreme-values existed in the first region. 17.The de-interlacing method according to claim 14, wherein the controlsignal indicates a second region associated with the target pixel. 18.The de-interlacing method according to claim 17, wherein the step ofgenerating similarity of the at least one possible edge angle generatessimilarity of the at least one possible edge angle of a plurality ofpixel pairs of the first display line and the second display line in thesecond region.
 19. The de-interlacing method according to claim 18,wherein the step of selecting the preferred edge angle selects thepreferred edge angle by comparing the similarity of the at least onepossible edge angle.
 20. The de-interlacing method according to claim14, further comprising an extreme-value detecting step for detectingpositions of extreme values in a third region associated with the targetpixel to output a prediction signal for indicating a predicted angleregion.
 21. An edge adaptive de-interlacing method for de-interlacing atarget pixel, comprising: detecting complexity associated with thetarget pixel, comprising: detecting a first complexity of a luminancedistribution curve of a first display line in a first region associatedwith the target pixel to output a first determination signal; detectinga second complexity of a luminance distribution curve of a seconddisplay line in the first region to output a second determinationsignal; and performing a logic operation according to the firstdetermination signal and the second determination signal to output acontrol signal;; performing an adaptive edge detection according to thecontrol signal to determine a preferred edge angle; and generating pixeldata of the target pixel according to the preferred edge angle.
 22. Thede-interlacing method according to claim 21, wherein in the step ofperforming an adaptive edge detection, a window processing region isdetermined according to the control signal.
 23. The de-interlacingmethod according to claim 22, wherein in the step of performing anadaptive edge detection, the higher the complexity associated with thetarget pixel is, the smaller the window processing region is.